GB165986A - Apparatus for utilising an alternating current of a given frequency to produce an alternating current or alternating magnetic flux of a different frequency - Google Patents

Abstract

165,986. Igranic Electric Co., Ltd., (Cutler-Hammer Manufacturing Co.). April 22, 1920. Vapour and vacuum or low-pressure apparatus, arrangements of; frequency, changing.-An alternating magnetic flux or alternating current of a given frequency is produced from a source of alternating current of a different frequency by means of electron-discharge devices which rectify the supplied current and produce therefrom intermittent pulsatory currents of the given frequency and of a given displacement, from which the alternating magnetic flux or current is obtained. In the arrangement shown, three-phase current from the lines L, L<1>, L<2> is supplied to the electronic device 1 through a transformer T comprising delta-connected primary windings 2, 3, 4 and two sets of star-connected six-phase secondary windings 5 - - 10. The device 1 is provided with a single cathode 15 and two sets of six anodes 16 - - 21, each anode being connected to one of the secondary windings 5 - - 10. The cathode is connected to the star points of the secondary windings through windings 12, 13, the connections being such that the rectified currents produced in the device 1 traverse these windings in opposite directions. Between each set of anodes and the cathode are placed grids 22, 23. A generator G producing current of the given frequency is provided with two sets of slip-rings 25, 26, arranged to, produce potentials displaced by 180‹, the rings of each set being connected to the grids and cathode as shown. The rings are preferably insulated through half their circumference and batteries 27 may be included between the rings and the grids. The generator is excited through an adjustable resistance r from a batter 24, which also serves to heat the cathode. Intermittent pulsatory currents are thus produced alternately in the windings 12, 13, and these currents may be employed to produce an alternating flux in the stator windings of a motor, or an alternating current in a secondary winding 14. Specification 165,935 is referred to.